Dimethylamine. Determining in workplace air with high-performance liquid chromatography (HPLC )
Journal Title: Podstawy i Metody Oceny Środowiska Pracy - Year 2015, Vol 31, Issue 3
Abstract
Dimethylamine (DMA) is a colorless flammable gas with an ammonia- or fish-like odor. It is used in manufacturing pesticides, pharmaceuticals, as an accelerator in vulcanizing rubber, and as a dehairing agent in the tanning industry. It is also widely used in chemical and textile industries. Occupational exposure to DMA vapours can cause irritation of the respiratory tract or serious injuries to eyes or skin.The aim of this study was to develop and validate a sensitive method for determining DMA concentrations in workplace air in the range from 1/10 to 2 MAC values (maximum admissible concentration), in accordance with the requirements of standard PN-EN 482.Studies was performed using high-performance liquid chromatography (HPLC). A Waters Alliance 2695 liquid chromatograph equipped with a quaternary pump, Waters Symmetry C-18 (150x2.1 mm; 5 μm) analytical column, spectrophotometric detector (UV-VIS), spectrofluorimetric detector (FLD) and autosampler were used for chromatographic separations. This method is based on the adsorption of DMA on silica gel coated with 2 M/L hydrochloric acid (HCl). The adsorbed compound is eluted with a mixture of acetonitrile and water and then derivatized with 9-fluorenylmethyl chloroformate (FMOC-Cl). Extraction efficiency of DMA from silica gel coated with HCl was 98,6 %. Samples of DMA on silica gel coated with HCl can be stored in a refrigerator for up to 10 days. Application of a Waters Symmetry column eluted with mixture of acetonitrile and water (62:38) made it possible to selectively determine DMA in a mixture of other amines. This method is precise and accurate (r = 0.999) within the investigated working range of 0.33 ÷ 13.3 g/ml (0.6 g/ml to 24 g/ml DMA-HCl), which is equivalent to air concentrations from 0.17 to 6.64 mg/m3 for a 10-L air sample. The limit of quantification (LOQ) for UV-VIS and FLD detectors was 0.14 and 0.035 μg/ml, respectively.The analytical method described in this paper made it possible to selectively determine DMA in workplace air at concentrations from 0.17 to 6.64 mg/m3. This method is precise, accurate and it meets the criteria for procedures for measuring chemical agents listed in EN 482:2006. This method can be used for assessing occupational exposure to DMA and associated risk to workers’ health. The developed method of determining dimethylamine has been recorded as an analytical procedure (see Appendix).
Authors and Affiliations
Marzena Bonczarowska, Sławomir Brzeźnicki
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